The Asteroid Belt

Guess what?

An asteroid is a rocky body in space which may be only a few hundred feet
wide or it may be several hundred miles wide. They are considered to be debris
left over from the formation of the solar system. Many asteroids orbit the Sun
in a region between Mars and Jupiter. This "belt" of asteroids
follows a slightly elliptical path as it orbits the Sun in the same direction
as the planets. It takes anywhere from three to six Earth years for a complete
revolution around the Sun. An asteroid may be pulled out of its
orbit by
the
gravitational pull of a larger object such as a planet. Once an asteroid
is captured by the gravitational pull of a planet, it may become a
satellite of that planet.
Astronomers theorize that is how the two satellites of Mars,
Phobos and Deimos, came to
orbit that planet. An asteroid is also capable of colliding with a planet
resulting in the formation of an impact crater. Some scientists believe that
just such an impact in the area of the Yucatan Peninsula in Mexico started the
chain of events which led to the extinction of the dinosaurs here on Earth.
Astronomers think that if it were not for the giant planet Jupiter exerting
its gravitational force on the asteroids in the belt, the inner planets would
be constantly bombarded by large asteroids. The presence of Jupiter actually
protects Mercury, Venus, Earth, and Mars from repeated asteroid
collisions!